Language & the Mind Animal Communication LING240 Summer...
Transcript of Language & the Mind Animal Communication LING240 Summer...
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Language & the MindLING240
Summer Session II 2005
Lecture 2Animal Communication &
Human Instincts
Animal Communication
• Are we special among species?• What are other species capable of?
• Are language-learning abilitiesrelated to general cognitivecapacities?
• Could language have evolvedgradually?
Naturally-Occurring Systems
• Monkey alarm calls
• Bee Dance
• Birdsong
Vervet Monkey Alarm Calls• 3 classes of predators• 3 distinct alarm calls• Packmates respond
appropriately even if predatoris not visible
• Loud bark (leopard alarm) =run for tree
• “cough” (eagle alarm) = rushinto the bushes
• “chutter” (snake alarm) =stand up & scan ground
What a vervet cannot express
• “I saw a snake near that tree just theother day, so watch your feet.”
• “Where did you say that leopard was?”
• “Can you say that again? - I didn’thear you.”
Dance of the Honeybees
• Conveyslocation ofsource ofnectar - everymessage isunique
‘deciphered’ by Karl von Frisch, 1919 & onward
Under 50 m away Over 50 m away:encodes distance& direction - isencoding of 2Dspace (a bee’s“mental map”)
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HoneybeeConversations
• Honeybees can express more thanvervets - but the conceptual contentis always “the location of what weare all looking for right now”
What a honeybee cannot express
• “There’s going to be some greatnectar at this really nice spot I knowsoon since the flowers are all inbloom.”
• “I saw a really swank hive a littleways from here - we should totallytake over and get ourselves somebetter digs.”
Sparrow Song
song call
• Song is highly structured -notes, syllables, phrases
• Regional variation• Sensitive period• Fixed meaning
Variation in Sparrow Song
Bird 1 Bird 2
Dialects of theWhite-CrownedSparrow(Marler, 1970)
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Nature & Nurture
• So birdsong seems to have both aninnate component and a learnedcomponent
• We still classify it as an instinct
Features of Human Language
• Creativity• Arbitrariness• Systematicity (e.g. word order,
structure)• Displaced reference• Pretense
Some Thoughts• Animal communication systems are quite
varied• Many features of human language found in
other species• Features of human language never combined
in other species• Extent of human linguistic creativity far
surpasses any other species• But… interesting lessons for human language
from studying related systems, e.g. birdsong
Teaching Human-like Language
• Can other species master propertiesof human language such as…– sounds– arbitrary words/signs to refer to object– systematic combinations of signs– creative use of sign combinations
• Are humans unique in the ability to dothis?
Alex
• Grey parrot, born 1976• Trained by Dr Irene Pepperberg (U.
Arizona) since 1977• Impressive ability to speak/understand
…for a parrot
Alex
• Grey parrot, born 1976• Trained by Dr Irene Pepperberg (U.
Arizona) since 1977• Impressive ability to speak/understand
…for a parrot
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Alex’s Language
• Speech sounds remarkably accurate…produced very differently from humans
• Knows names of 100+ objects plussome fixed expressions
• Answers simple questions about objects(e.g. about size, color, material)
• Requires immense amounts of training
Washoe & Nim Chimpsky
• Apes taught modified sign languagein 1960s & 1970s
Washoe & Nim Chimpsky
• Learned many signs• Able to combine signs• Sign combinations lacked systematic
use of word order etc.• Impressive, but far behind 2-year olds
Kanzi
• Benobo (‘pygmy chimp’)• Born 1980• Yerkes Regional Primate Center, Atlanta
Trained by Sue Savage-Rumbaugh &others
• Grew up with an adult benobo, who wasbeing trained to communicate with‘pictograms’, with little success
• Kanzi quickly surpassed his guardian
Kanzi
• Pictograms remove articulationdifficulty
• Impressive creativity andsystematicity - best shown to-date
• Still falls short of 2-year olds
Creativity in Human Language• Animal languages have a fixed,
limited range of messages (vervetcalls, bee dance, bird song)
• Human language is infinitely creative• Increased expressive power of human
language is not just a difference ofdegree - human language isfundamentally different
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Creativity in Human Language
• Creativity of human language resultsfrom its combinatorial properties
• Small number of memorized “pieces”yield vast range of possible messages
• Human “pieces” are sounds, words,and phrases
Language vs. Communication
• Communication: conveying information between amessenge-sender and a message-receiver
• Language: one type of communication systemused by human beings, and the only one we areaware of in any species that takes a finite numberof “pieces” and combines them with a finite set ofcombinatorial rules to yield an infinite number ofmessages about any topic.
So what is it that humans learn?
Option 1:• Other species can master the
rudiments of human language• Human language is not a major
departure from other species• Evolutionary precursors to human
language
So what is it that humans learn?
Option 2:• Very little - similar to teaching bees the
bee dance!• Other species are not ‘designed’ for
human language• Learn how human instincts work by
studying humans!
Some More Thoughts
• Examination of other species clarifies howunusual human language is
• Other species have interestingcommunicative tricks - different from ours
• Some species can learn some impressive‘language tricks’ … doesn’t teach us muchabout how human language works
Someone Else’s Thoughts
The fact that a dog can be trained to walk on its hindlegs does not prejudice the claim that bipedal gait isgenetically coded in humans. The fact that we canlearn to whistle like a lark does not prejudice thespecies-specificity of birdsong.
(Fodor, Bever & Garrett, 1974The Psychology of Language)
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So let’s talk about this“instinct” thing…
• Bats use sonar to echolocate; homingpigeons know where home is; deer rubantlers against trees; spiders spin webs;dolphins play; some primates walk
• Special properties of individual species, notrelated to “general intelligence”, developautomatically
• Another “instinct”: human language
Why do humans have language?
• Because we’re smarter than other animals?• Because we have a bigger brain?• Because our mouths have a special shape?• Because somebody took the time to teach
us?
• …or because that’s just something thathumans do?
Why call language an instinct?
• Species specificity• Uniformity throughout human species• Humans spontaneously create languages• Independence from other mental abilities• Sensitive period for learning language
Why call language an instinct?
• Species specificity• Uniformity throughout human species• Humans spontaneously create languages• Independence from other mental abilities• Sensitive period for learning language
Species Specificity
• Other species simply can’t learnhuman language
• The communication systems of otheranimals are not even remotely ascomplex as human language.
The point
“We may not be able to take flight byflapping our upper extremities, but weare the only species known that canrationally discuss our inability to do so.”
-Stephen Anderson, Doctor Dolittle’sDelusion
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Why call language an instinct?
• Species specificity• Uniformity throughout human species• Humans spontaneously create languages• Independence from other mental abilities• Sensitive period for learning language
Uniformity
• All humans master a human language …except in extreme circumstances
• All human languages are remarkablysimilar in their basic properties.
Uniformity• All human languages are able to express an
infinite number of never-before-expressedsentences
• All are able to express ideas of a similar levelof complexity
• Even the form of languages seems to vary inrestricted ways
Why call language an instinct?
• Species specificity• Uniformity throughout human species• Humans spontaneously create languages• Independence from other mental abilities• Sensitive period for learning language
Humans Spontaneously CreateLanguage: Everyday cases
• Poverty of the Stimulus: Every childhas to go beyond the data heard inthe environment.
• Children acquire many linguisticgeneralizations that experience couldnot have made available
Something heard & learned…
• Who did Jareth see Sarah with in hiscrystal?
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Something unheard but stilllearned…
• *Who did Jareth see Sarah and in hiscrystal?
Every child has to go beyondthe environment
• Children cannot hear every possible sentenceof their native language
• Children never hear impossible sentences
• Both of these sets are infinitely large, yet weall end up generally agreeing about which onesare possible and which ones are impossible
Children create their own system
“It breaked.”
“Don’t giggle me!”
“Does she doesn’t like that?”
“What she does eat?”
Children spontaneously createlanguage: Extreme cases
• Input is totally absent - home signsystems of deaf children
• Input is inconsistent - Simon
• Input is not a full language - pidgins andcreoles
Children spontaneously createlanguage: Extreme Cases
• Input is totally absent - home signsystems of deaf children
• Input is inconsistent - Simon
• Input is not a full language - pidgins andcreoles
Simon (Singleton & Newport)Input:
- Parents were late learners of ASL- Parents used required ASL verb inflections 60% ofthe time (either omitted them or used the wrong ones)- In school, only exposed to a signed English system
Output:- As good as “native of native” children on mostaspects of ASL inflection- Simon’s own use of verbs of motion surpasses theperformance of his parents- Simon does not acquire the “noise” of his parents -he regularizes the irregular input from his parents.
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Children spontaneously createlanguage: Extreme Cases
• Input is totally absent - home signsystems of deaf children
• Input is inconsistent - Simon
• Input is not a full language - pidgins andcreoles
Pidgins & Creoles: TheCase of Nicaraguan Sign
Language• 1977: Center for special education opened (100 children by
1979)• 1980: Vocational school for adolescents opened (400
students in the two schools by 1983)• 1986: Social club for deaf adolescents and adults formed
(by 1990, this was the National Association of DeafNicaraguans)
• “First Cohort” of children formed a pidgin based on theircollective homesign systems: Lenguaje de SignosNicaraguense (LSN)
• “Second Cohort” received pidgin LSN as input and nativizedthis “inconsistent and insufficient input” to produce acreole: Idioma de Signos Nicaraguense (ISN)
Nicaraguan Sign Language:A Test of Performance
• 25 children, aged 7-31 yrs at time of testing• Age of entry into community:
– Young (birth to 6;6), n=8– Medium (6;7 to 10;0), n=8– Old (10;1 to 27;5), n= 9
• Year of entry into community:– Before 1983– 1983 or earlier
To Sum Up
• Signers who entered the community at ayounger age…– Express more events overall– Express more verbs per unit of time– Inflect more verbs (location, person, number,
agreement)– Use more classifiers (size-and-shape, object-
category)– Use fewer pantomined (body-anchored) gestures
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Why call language an instinct?
• Species specificity• Uniformity throughout human species• Humans spontaneously create languages• Independence from other mental abilities• Sensitive period for learning language
Language & General Intelligence
• Good language with poor overall cognitiveprofile:– Williams Syndrome
• Poor language with good overall cognitiveprofile:– Pure Word Deafness– Broca’s Aphasia– Specific Language Impairment.
• “Double Dissociation” argument
Williams Syndrome
Severe impairments,Good language
Cognitive Characteristics ofWilliams Syndrome
• Low general IQ (50-60)• Poor math• Poor visuospatial reconstruction abilities• Good language• Often good with music• Highly social
Copying Simple PicturesModel
WSAge 11
WSAge 11
ControlAge 6
Model
WilliamsAge 11;1KBIT 70(RA)
WilliamsAge 9;1KBIT 77(AS)
ControlAge 6;1KBIT 122(BD)
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Describing Complex Pictures
“Bill is looking at the cow that the boy is pointing, andMax is looking at the cow that the girl is pointing at.”(WS, IQ approx. 40)
(Zukowski 2001)
Pure Word Deafness
Normally functioning people,Unable to hear words
AuditoryInput
AuditoryObjectRecognition
AuditoryWordRecognition
Broca’s Aphasia• Identified 1861, Paul Broca• Patient “Tan”: intelligent, good
language comprehension,severe speech deficit
• Died soon afterwards: brainshowed selective damage atjunction of frontal, parietal,temporal lobes, left hemisphere
Broca’s Aphasia
Broca’s Aphasia - Production
Typical clinical symptoms of Broca’s aphasics:“Yes ... Monday ... Dad, and Dad ... hospital,
and ... Wednesday, Wednesday, nine o’clockand ... Thursday, ten o’clock ... doctors, two,two ... doctors and ... teeth, yah. And adoctor ... girl, and gums, and I.”
“Me ... build-ing ... chairs, no, no cab-in-ets.One, saw ... then, cutting wood ... working ...”
Broca’s Aphasia - Comprehension
1a. “The cat chased the dog.” active1b. “The cat was chased by the dog.” passive
2a. “I showed her baby pictures.” ambiguous
2b. “I showed her baby the pictures.” unambiguous2c. “I showed her the baby pictures.” unambiguous
‘Function Words’
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Specific Language Impairment
• Genetic disorder, currently poorly understood• Good general cognitive abilities, poor language
“It’s a flying finches, they are.”“She remembered when she hurts herself the
other day.”“The neighbors phone the ambulance because
the man fall off the tree.”“The boys eat four cookie.”“Carol is cry in the church.”
Why call language an instinct?
• Species specificity• Uniformity throughout human species• Humans spontaneously create languages• Independence from other mental abilities• Sensitive period for learning language
Sensitive Period forLearning Language
• Language learning is effortless beforepuberty, extremely effortful later in life
• Applies to both first and secondlanguage learning
• Applies to spoken and signed languages• Sensitive periods familiar from
‘instincts’ in other species
What is a “sensitive” or“critical” period?
“A period of development during whichsome crucial experience will have itspeak effect on development orlearning, resulting in normal behaviorattuned to the particular environmentto which the organism has beenexposed.” - Newport
Examples of critical periods inother species
• Species: ducks• What they learn: attachment to their
mothers (imprinting)• Critical period for this “learning”:
- 9-21 hours after hatching- After 21 hours, less likely to form anattachment
Examples of critical periods inother species
• Species: White-crowned sparrow• What they learn: their species’ mating song
(from hearing adults sing it)• Critical period for “learning”:
- 7-60 days after birth (to fully acquire song)- 60-100 days after birth (to acquire skeletalbasics of song)- After 100 days of age, bird will never singnormally
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A critical period for FIRSTlanguage acquisition
• Case Studies:- Isabelle- Genie- Chelsea
• A special population: deaf children born tohearing parents
Case Studies: Isabelle(Davis, 1947)
• Family background: Hidden in atticby deranged mother, never spoken to
• Discovered at age 6: had no speech,at cognitive level of 2 year old
• Outcome: Within 1 year, she caughtup with other 7 year olds
Case Studies: Genie(Curtiss, 1977)
• Family background: From 18 months onward, livedtied to a chair in a darkened room, frequentybeaten, never spoken to
• Discovered at age 13, had no speech• Outcome: Learned a large vocabulary, but syntax
and morphology never fully developed
• “Man motorcycle have”• “Genie full stomach”• “Want Curtiss play piano”
Case Studies: Chelsea(Curtiss, 1989)
• Family background: A partially deaf womanincorrectly diagnosed as “retarded”
• Discovered at age 31, and fitted with hearing aids• Outcome: Learned a large vocabulary, but syntax
and morphology even worse than Genie
• “Breakfast eating girl”• “Banana the eat”
A Special Population: Deafchildren born to hearing parents
(Newport, 1990)
• Examined ASL proficiency in people whohad been using ASL for 30 years
• But different ages of first exposure to ASL:– Native/early learners: between birth and age 6– Late learners: after age 12
A Special Population: Deafchildren born to hearing parents
(Newport, 1990)
• Basic result: Before age 6 > After age12
• One Exception: Word order uniformlygood for all learners
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A Critical Period for SECONDLanguage Acquisition (Johnson
and Newport, 1989)
• Examined English proficiency in Koreanand Chinese immigrants to the U.S. whohad lived here at least 5 years
• Again, different ages of first exposure(anywhere between 3 and 39 years old)
Test from Johnsonand Newport (1989)
• Hear recorded sentences & judgewhether GOOD or BAD
“The farmer bought two pig at the market.”“Tom is reading book in bathtub.”
Results: SecondLanguage Acquisition
Sum Up: Critical Period
• Language learning is effortless beforepuberty, extremely effortful after
• Applies to both first and second languagelearning
• Applies to spoken and signed languages• Critical periods familiar from biologically-
programmed abilities in other species
Concluding Thoughts
• Language is specific to humans, andextremely uniform among humans
• Humans create language withoutinstruction
• Language abilities are partly independentof other cognitive abilities
• Language learning requires a young brain• Thefore…language seems to have the
properties of an ‘instinct’
But…• Identifying language as a human
instinct is just the first step
• It tells us nothing about how thisinstinct works, how it develops, how itis encoded in the brain or in thegenome...